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I have a XG10000E generator that I use for back up power at my home. I would like to be able to run electronics on it (internet modem, TV, computer). Is there a way to filter the Total Harmonic Distortion to keep my electronics from getting fried? I have considered buying a UPS to put between the generator and my electronics but I'm not sure if this would help.
 

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Harmonic distortion

Hi jas42,

It is not a simple problem, the Generac XG series has a total harmonic distortion from 4.7 t0 25% , the XP series, less than 5%. But what is THD?.

The AC voltage supplied by the grid has a sinusoidal form (as shown in the next post) , very near to the ideal smooth curve represented by the math function sine. The main characteristic of this ideal curve is that it has not sharp changes in its trajectory. When this curve is converted in voltage, and is fed to a resistive device, such as an incandescent lamp, it impulses a current with the same wave form, a smooth variable current waveform.

Any deviation from this ideal sine waveform is called distortion. In the AC supplied by the grid, there are many big generators carefully designed to produce the best waveform and quality electrical power. In a 60 cycles per second (60 Hz) system, this frequency is named the fundamental frequency.

Due to design difficulties and costs, many portable generators produce not only a non sinusoidal waveform but more than the funamental frequency; along with the 60Hz, there are multiples of this freq., double, triple etc and they are called harmonics.

If the fundamental frequency is 60 cycles per second, at to say 120 volts, the other unwanted frequencies, especially the third harmonic (180 Hz), are present in a variable amount, to say 5volts, 12 volts etc. the fifth may be 3 volts in example. The sum up of the total amount of unwanted voltages, generated at frequencies different to 60 Hz, expressed as a percentage of the the fundamental 60 Hz 120 volts, is called Total Harmonic Distortion.

This THD, is fed mixed with the 60 Hz, deforming the smooth curve, and depending of the load, may or may not be too harmful. An incandescet lamp or a portable drill are not affected, but a sofisticated electronic control may be alterated in its functions seriously, induction motors may overheat, as power transformers.

To filter this harmonics, there are special harmonic filters. Most common filters or economic line conditioners, merely filter out spikes or noise, regulators mantain line voltage inside safe margins, but to avoid harmonics out of your delicate electronics, you will need dedicated harmonic filters, that will control spikes too.

An UPS (uninterruptible power supply), may or not may solve the problem.
Be aware of simple UPS that will provide an horrible "square" wave full of power spikes and deformations ( see the photo) that will harm anything but an incandescent lamp. There are other that provide a "modified sine wave", similar to the produced by the common inverters, better than square . The pure sine wave inverters or UPS produce a clean, distortless voltage wave appropiate for all kind of equipment.

But, UPSs and inverters (domestic) run on low voltage DC current. UPSs have an internal battery, used only when normal AC supply is cut. Most of them (the small ones ) have a by pass relay to feed directly the protected equipment with the AC mains. The true online UPSs convert the AC supply to DC and then generates an AC sinusoidal, clean voltage wave, independent of the incomming supply. This is a solution, costly but solution.

The other solution would be exchange your generator for an XP10000.

In few words:

Harmonic filter, true online UPS, XP10000 genset, or take the risk to damage your equipment.

Best regards.
 

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Waveforms

Hi,

Today I have taken some snapshots from the screen of an oscilloscope, to see real waveforms (1) from the grid, (2) a pure sine wave from a good quality UPS, (3) a square wave from a cheap UPS and (4) the equipment used, all of them feeding a 50 W incandescent lamp, which will not alter the waveform of any of the power supplies.

Oscilloscope Technology Neon Electronic device Neon sign


Technology Oscilloscope Electronic device Neon Neon sign


Oscilloscope Technology Electronic device Electronics Screen


Electronics Technology Electronic device Electronic instrument Wire
 

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Pure sine wave

Hi jas42,

Another solution would be to feed, in a separate circuit, all your "delicate electronic equipment" with an aditional inverter generator, a small one, enough to mantain running it, plus some led lights. I have seen a Generac iX800 for $ 287 in Ebay:

Generac IX800 800 Watt Portable Inverter Generator 696471057911 | eBay.

An advantage with this genset is the low noise emitted due to its size, permitting to install it near to the usage point, but of course always outdoors.

This kind of generator produce a very clean sine wave with exactly 60 Hz through all the power range, adecuate for the most sensitive electronic equipment .

Regards
 

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I have a XG10000E generator that I use for back up power at my home. I would like to be able to run electronics on it (internet modem, TV, computer). Is there a way to filter the Total Harmonic Distortion to keep my electronics from getting fried? I have considered buying a UPS to put between the generator and my electronics but I'm not sure if this would help.
Did you ever solve this? We have a CAT 12k watt generator but the Cyberpower UPS batteries we bought won't accept the power from the generator. I'm thinking the next thing I'll try is adding a power conditioner between the generator and UPS, but I'm not sure if that will help anything
 

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IMHO, "Home Electronics" can survive in a much worse electrical environment than you'd be subjecting it to. There are a lot of "Very Cost Effective" (cheap) gensets out there running same.

Wow! Over five years later and I still totally agree with this and have gone though several more outages with open frame generators powering "sensitive electronics" and normal house loads, frig, freezer.

Osviur nailed the description and options for dealing with THD for those that think it's an issue. Utility power is considered the gold standard or something for "power purity." It ain't. In a steady state scenario, it is clean and the frequency is solid, when perturbations are added, switching, storms, etc. all kinds of spikes, surges, dips, etc. appear. IME more damage is caused when power is restored, particularly if the restoration isn't "solid" and dips or chatters. Please remember that THD is also a function of load, as the load varies, so does THD. So, on utility power, whatever is turning on and off and interacting in your house is ignored by the sheer...power... of the utility feed. e.g. My house has a 200Amp service, so that's 48,000Watts available at a very stiff 60 Hz. Compare that 48KW to a 5-10KW generator and its ability to "ignore" load changes as things turn on and off. Does the vast majority of things in your house care? Nope. Reports I've read here and on other forums talked about portable generators and UPS not playing together nicely. When you consider the purpose of a UPS it's to provide the ultimate in clean power to a load, It constantly monitors the incoming power and allows it to pass through to the load, at the slightest disturbance it isolates and goes on battery. Not surprising the UPS wouldn't like generator power. The UPS is doing what it's designed to do, the question is, do you need a UPS for a normal household? If you do, get an inverter generator. IMO power conditioners are a waste of money, to be effective, they have to be designed for a particular application, generic ones are generic.

I don't recall seeing any posts about inexpensive generators "frying" electronics? there have been posts about incompatibility with very upscale furnaces and frigs. Also, Generac seems to have the whole house generator market pretty much cornered with open frame generators and have yet to see THD numbers available on those?
 

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Agreed ... As best I can tell, there isn't a THD problem at our level of home power requirements. I use only open-frame gennys with varying levels of thd, from 10% to 25%. Nothing in the house really complains, seems to die an early death, or exhibits any other power oddity. THD is perhaps more of a sales thing ...

Home-quality UPS's are an issue, but this may be due to varying levels of design and quality, coupled with not being intended for home generators in the first place. I've had some that wouldn't run at all on genny (cyberpower), others than ran a bit better (apc), but almost all didn't like genny power. There is also theory out there that these and other home-class devices throw THD back out on the home wiring, no matter what kind of power got to them in the first place.

Audiophile equipment, ham radio shacks ... these all are possible exceptions to the rule for THD doesn't matter" statement, but then, folks usually address the incoming power issue in these specialty cases anyway.

One caveat I've come to understand is that, being off-grid, I already have a power conditioner in place ... for the whole house. It's the magnum 4024 pure sine wave inverter/charger, coupled with LiFePO4 battery bank. This inverter/charger happily consumes any kind of power from any genny, and feeds it to the battery bank. Input is high THD power, output is pure sine wave power. Even here, it probably stays clean only until it hits all the crummy consumer-class equipment beyond, and goes downhill from there.

While an expensive solution, this points to one other way to solve such THD concerns; it could theoretically work on-grid. Grid-tie solar solutions (with battery bank) are also whole-house power conditoners. You wouldn't need datacenter grade ups/power conditioners (these are also very expensive). Just integrate a grid-tied or parallel inverter/charger & battery-bank, priced/sized to the load.

Another theory is that most modern consumer-class equipment defends its own turf inside (converts any kind of incoming ac to dc, then back to clean ac), but doesn't care about any other device on the house wiring (not concerned with possibly throwing THD back out). I don't have enough test points and equipment to see what's happening everywhere, although I'm trying to get there ... this is a huge ongoing effort ... oscilloscopes, breakout plugs, etc..

Multiple problems to pick from, and attempt to solve ...
 

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Great stuff!

That's been my contention all along.... I haven't seen nor heard non-inverter generators causing havoc to "sensitive" electronics despite all the marketing propaganda against them. Though, it's not that they're lying. It's just something that's been grossly exaggerated.

That said, if given a choice and with all else being equal, I would obviously go for an inverter generator (less noise and better fuel efficiency). However, it's not going to be a deal-breaker.
 

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Looks like OP never came back.

My Firman is rated pretty high on the THD scale but I've not had any issues powering anything with it. When I used it after Ida, it was to make coffee in a percolator. It worked fine. Next time, I'll use it to power a portable hot plate to heat up food as well.
 

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The AC voltage supplied by the grid has a sinusoidal form (as shown in the next post) , very near to the ideal smooth curve represented by the math function sine. The main characteristic of this ideal curve is that it has not sharp changes in its trajectory. When this curve is converted in voltage, and is fed to a resistive device, such as an incandescent lamp, it impulses a current with the same wave form, a smooth variable current waveform.
So thats why my halogen lamp flickers with the generator then?

Did you ever solve this? We have a CAT 12k watt generator but the Cyberpower UPS batteries we bought won't accept the power from the generator. I'm thinking the next thing I'll try is adding a power conditioner between the generator and UPS, but I'm not sure if that will help anything
A UPS main purpose is to provide constant power without spikes, but a generator's power is up and down constantly, so the UPS wont accept the power and stays on battery mode..... So you need either a good "inverter generator" or a "generator friendly UPS to fix this problem, but a line conditioner might also do the job.
 

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15 years ago, I ran I.T. for Konica Photo Imaging. In our photofinishing headquarters location, we had a big Cat diesel generator in case of emergencies. It fed 3phase 208V via a transfer switch into a line conditioner/converter that generated clean 120/240V and in turn into a 20KVA Toshiba UPS. That was the only way to keep it all happy.
 

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So thats why my halogen lamp flickers with the generator then?
Halogen and incandescent bulbs are essentially the same except for the type of gas in the bulb. Argon for incandescent, halogen for halogen. Neither should flicker unless the power quality I’d very poor.

Led bulbs on the other hand are far more likely to flicker especially if on a dimmer switch. Pricier better quality led bulb are less prone then the cheap ones. My cheap Led bulbs will flicker on grid power on occasion but do not when powered by my eu7000s.
 

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Halogen and incandescent bulbs are essentially the same except for the type of gas in the bulb. Argon for incandescent, halogen for halogen. Neither should flicker unless the power quality I’d very poor.

Led bulbs on the other hand are far more likely to flicker especially if on a dimmer switch. Pricier better quality led bulb are less prone then the cheap ones. My cheap Led bulbs will flicker on grid power on occasion but do not when powered by my eu7000s.
Led bulbs seem to run fine, no flickering. I haven't tried a ones with a dimmer switch though.... I run my halogen lamp through my UPS connected to the generator and this solves the flickering.
 

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Agreed ... As best I can tell, there isn't a THD problem at our level of home power requirements. I use only open-frame gennys with varying levels of thd, from 10% to 25%. Nothing in the house really complains, seems to die an early death, or exhibits any other power oddity. THD is perhaps more of a sales thing ...

Home-quality UPS's are an issue, but this may be due to varying levels of design and quality, coupled with not being intended for home generators in the first place. I've had some that wouldn't run at all on genny (cyberpower), others than ran a bit better (apc), but almost all didn't like genny power. There is also theory out there that these and other home-class devices throw THD back out on the home wiring, no matter what kind of power got to them in the first place.

Audiophile equipment, ham radio shacks ... these all are possible exceptions to the rule for THD doesn't matter" statement, but then, folks usually address the incoming power issue in these specialty cases anyway.

One caveat I've come to understand is that, being off-grid, I already have a power conditioner in place ... for the whole house. It's the magnum 4024 pure sine wave inverter/charger, coupled with LiFePO4 battery bank. This inverter/charger happily consumes any kind of power from any genny, and feeds it to the battery bank. Input is high THD power, output is pure sine wave power. Even here, it probably stays clean only until it hits all the crummy consumer-class equipment beyond, and goes downhill from there.

While an expensive solution, this points to one other way to solve such THD concerns; it could theoretically work on-grid. Grid-tie solar solutions (with battery bank) are also whole-house power conditoners. You wouldn't need datacenter grade ups/power conditioners (these are also very expensive). Just integrate a grid-tied or parallel inverter/charger & battery-bank, priced/sized to the load.

Another theory is that most modern consumer-class equipment defends its own turf inside (converts any kind of incoming ac to dc, then back to clean ac), but doesn't care about any other device on the house wiring (not concerned with possibly throwing THD back out). I don't have enough test points and equipment to see what's happening everywhere, although I'm trying to get there ... this is a huge ongoing effort ... oscilloscopes, breakout plugs, etc..

Multiple problems to pick from, and attempt to solve ...
That inverter is quite the solution.
Probably not going to make that kind of investment but would you mind describing the setup? Just interested as I’d like to know what options there are for a reasonable solution to clean high THD. It looks like this is a 24v input to a 120v pure sine wave output. How do you use it with a 120 or 240 gen set.
thanks.
 

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"There is also theory out there that these and other home-class devices throw THD back out on the home wiring, no matter what kind of power got to them in the first place."

This is not a theory ... this is a physical fact.


"One caveat I've come to understand is that, being off-grid, I already have a power conditioner in place ... for the whole house. It's the magnum 4024 pure sine wave inverter/charger, coupled with LiFePO4 battery bank. This inverter/charger happily consumes any kind of power from any genny, and feeds it to the battery bank. Input is high THD power, output is pure sine wave power. Even here, it probably stays clean only until it hits all the crummy consumer-class equipment beyond, and goes downhill from there."

This inverter charger has a DC input. I guess to run from Solar. How can this accept AC output from a generator?
 

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This inverter charger has a DC input. I guess to run from Solar. How can this accept AC output from a generator?
Good question. I would've conceded that this product is a do-all and accepts both DC from solar and AC from utility and process both into a self-generated pure sine wave. I took a peek at the specs but it just says it only accepts 18 - 33.6 VDC input.

On the THD front, I should mention that brushless generators tends to produce the dirtiest output. They're still being sold mostly on smaller (albeit, cheap) gens and in fact, sometimes even touting the "brushless" feature as a technological advantage. I'd stay clear of those unless you plan to use it exclusively for resistive loads.
 
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